/*
 * Copyright 2013 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package py.netty.core.twothreads;

import java.nio.channels.SelectionKey;
import java.util.AbstractSet;
import java.util.Arrays;
import java.util.Iterator;

final class SelectedSelectionKeySet extends AbstractSet<SelectionKey> {
  SelectionKey[] keys;
  int size;

  SelectedSelectionKeySet() {
    keys = new SelectionKey[1024];
  }

  @Override
  public boolean add(SelectionKey o) {
    if (o == null) {
      return false;
    }

    keys[size++] = o;
    if (size == keys.length) {
      increaseCapacity();
    }

    return true;
  }

  @Override
  public int size() {
    return size;
  }

  @Override
  public boolean remove(Object o) {
    return false;
  }

  @Override
  public boolean contains(Object o) {
    return false;
  }

  @Override
  public Iterator<SelectionKey> iterator() {
    throw new UnsupportedOperationException();
  }

  void reset() {
    reset(0);
  }

  void reset(int start) {
    Arrays.fill(keys, start, size, null);
    size = 0;
  }

  private void increaseCapacity() {
    SelectionKey[] newKeys = new SelectionKey[keys.length << 1];
    System.arraycopy(keys, 0, newKeys, 0, size);
    keys = newKeys;
  }
}
